docs(raw_vehicle_cmd_converter): update readme (autowarefoundation#5822)

Signed-off-by: Takamasa Horibe <[email protected]>

vehicle/raw_vehicle_cmd_converter/README.md

@@ -1,6 +1,28 @@
 # raw_vehicle_cmd_converter
 
-`raw_vehicle_command_converter` is a node that converts desired acceleration and velocity to mechanical input by using feed forward + feed back control (optional).
+## Overview
+
+The raw_vehicle_command_converter is a crucial node in vehicle automation systems, responsible for translating desired steering and acceleration inputs into specific vehicle control commands. This process is achieved through a combination of a lookup table and an optional feedback control system.
+
+### Lookup Table
+
+The core of the converter's functionality lies in its use of a CSV-formatted lookup table. This table encapsulates the relationship between the throttle/brake pedal (depending on your vehicle control interface) and the corresponding vehicle acceleration across various speeds. The converter utilizes this data to accurately translate target accelerations into appropriate throttle/brake values.
+
+![accel-brake-map-table](./figure/accel-brake-map-table.png)
+
+### Creation of Reference Data
+
+Reference data for the lookup table is generated through the following steps:
+
+1. **Data Collection**: On a flat road, a constant value command (e.g., throttle/brake pedal) is applied to accelerate or decelerate the vehicle.
+2. **Recording Data**: During this phase, both the IMU acceleration and vehicle velocity data are recorded.
+3. **CSV File Generation**: A CSV file is created, detailing the relationship between command values, vehicle speed, and resulting acceleration.
+
+Once the acceleration map is crafted, it should be loaded when the RawVehicleCmdConverter node is launched, with the file path defined in the launch file.
+
+### Auto-Calibration Tool
+
+For ease of calibration and adjustments to the lookup table, an auto-calibration tool is available. More information and instructions for this tool can be found [here](https://github.com/autowarefoundation/autoware.universe/blob/main/vehicle/accel_brake_map_calibrator/accel_brake_map_calibrator/README.md).
 
 ## Input topics